1. Field of the Invention
The present invention relates generally to a working machine, and in particular to a throttle adjusting apparatus for the machine having a throttle lever with which plural functions including the operation of a throttle valve are achieved.
2. Description of the Related Art
There are known throttle adjusting apparatuses for adjusting amounts by which throttle valves of carburetors provided in the proximity of engines are opened. One example of such apparatuses is disclosed in, for example, Japanese Utility Model Laid-Open Publication No. SHO 60-170290 entitled xe2x80x9cOPERATING APPARATUS FOR BICYCLE HAVING PRIME MOVERxe2x80x9d.
The disclosed apparatus is mounted on a handlebar of a bicycle. The apparatus includes a throttle lever positioned adjacent to a handgrip mounted on an end portion of the handlebar. The lever lies in a plane perpendicular to a longitudinal direction of an axis of the handgrip. The lever is designed to pivot on the axis. The apparatus also includes a throttle control cable connected to the throttle lever. When the throttle lever pivots on the axis, a throttle shaft disposed within a carburetor is operated by means of the throttle control cable. The apparatus further includes a switch lever lying in the plane perpendicular to the longitudinal direction of the axis. The switch lever is designed to pivot on the axis, as is the throttle lever. When the switch lever pivots to an on position, a prime mover of the bicycle is operated to drive a rear wheel of the bicycle.
However, it is difficult or troublesome for a rider to properly operate these two different types of levers because they are disposed closely to each other. For example, even if the rider attempts to operate one of the throttle lever and switch lever, he can inadvertently operate the other one.
Further, the throttle lever is positioned more closely to the handgrip than the switch lever. Thus, the throttle lever can hinder the rider from operating the switch lever.
It is therefore an object of the present invention to provide a throttle adjusting apparatus for a working machine including a single lever with which a plurality of functions including the operation of a throttle valve are achieved.
According to an aspect of the present invention, there is provided a throttle adjusting apparatus for a working machine, comprising: a throttle wire attachable to the working machine in such a manner as to extend along a longitudinal direction of a handle of the working machine, the throttle wire having one end portion connected to respective ones of a throttle valve, a choke valve, and a fuel cock; and a throttle lever pivotable in a plane perpendicular to a longitudinal direction of a grip of the handle, the throttle lever being connected to another end portion of the throttle wire, such that the throttle lever is operated to simultaneously adjust amounts by which respective ones of the throttle valve, the choke valve, and the fuel cock are opened.
The one end portion of the throttle wire is connected to respective ones of the throttle valve, the choke valve, and the fuel cock while another end portion of the throttle wire is connected to the throttle lever. Provision of the throttle lever makes it possible to simultaneously and coordinately adjust amounts by which respective ones of the throttle valve, the choke valve, and the fuel cock are opened. That is, the throttle lever is operated to open and close the choke valve and the fuel cock and to adjust the amount the throttle valve is opened.
The simultaneous and coordinated operations of the throttle lever, the choke valve, and the fuel cock can be achieved using the throttle lever alone to thereby provide improved operational performance of the working machine.
In a preferred form of the present invention, the fuel cock is in one of an opened position and a closed position when the throttle lever is in a minimum position where the throttle valve is opened a minimum amount, the choke valve being in one of an opened position and a closed position when the throttle layer is pivoted from the minimum position to a maximum position where the throttle valve is opened a maximum amount.
The amount of pivotal movement of the throttle lever determines whether the fuel cock and the choke valve are opened or closed, in addition to the amount by which the throttle valve is opened.
Alternatively stated, the pivotal movement of the throttle lever allows the simultaneous operations of the fuel cock, the choke valve, and the throttle valve.
The working machine can thus be rapidly and readily operated to thereby provide improved operational performance and working capacity thereof.
Further, the throttle lever is disposed proximate the grip. An operator can thus operate the throttle lever by his hand grasping the grip, so as to bring the engine into and out of operation as well as adjusting the amount by which the throttle valve is opened. With the throttle lever thus arranged, the operator need not move his hand a lot so as to perform the respective operations. The working machine can thus be made easy to operate. This results in improved operational performance of the working machine.
In a further preferred form of the present invention, the throttle adjusting apparatus further comprises an engine switch disposed proximate the handle of the working machine, the engine switch being operated to determine whether a spark plug of an engine of the working machine is supplied with a power required to produce a spark thereat.
The engine switch can be switched between an on state and an off state by the operator""s hand grasping the grip.
Because the engine switch is disposed proximate the handle rather than the engine, the operator need not bring his hand to the engine when operating the engine switch. This leads to improved operational performance of the working machine.
In a still further preferred form of the present invention, the one end portion of the throttle wire is connected to an engine switch, such that the engine switch is switched between an on state and an off state by means of the throttle lever, when the engine switch is in the on state, a spark plug of an engine of the working machine being supplied with a power required to produce a spark thereat, when the throttle lever is in the minimum position, the engine switch being in one of the on state and the off state.
The amount of pivotal movement of the throttle lever determines whether the fuel cock and the choke valve are opened or closed and whether the engine switch is switched to the on state or the off state, in addition to the amount the throttle valve is opened.
The engine switch can thus be operated with the throttle lever. With the thus arranged throttle lever, the working machine can be readily operated to provide improved operational performance and working capacity thereof.
The engine switch is not disposed proximate the engine but is connected to the throttle lever. The operator can thus operate the throttle lever by his hand grasping the grip, so as to bring the engine into and out of operation. The operator can operate the working machine with reduced burden imposed thereon.